Alkylthiohydroquinones-formaldehyde-amine reaction products and petroleum fractions, containing the same



United States Patent ALKYLTHIOHYDROQUINONESI FORMALDE- HYDEj-AMINEREACTION PRODUCTS.-

' PETRQLEUM, FRACTIONS. CONTAINING. I

THE SAME John; W. Brooks; Wenonah, N; J'., assignor to Socony- MobiLOilCompany; Inc a; corporation of-NeWYork NoD'rawing: Application May2'4, 1952,

Serial No. 289,888

18 Claims. (Cl. 252,47.5)

for use as lubricants are subject to oxidative deteriora tion under conditions of use in modern combustion en; gines. The oxidation products which are formed in the oil are acidic in nature and' exert a corrosive effect on the-metal'parts with. which the oil comes in contact. Alloy bearings, such as copper-lead, silver-cadmium; nickelcadmium, etc., which are widely used, are particularly subject to attack by theacidic oxidation products formed in the oil in use. Furthermore, these oxidation products produce formations; of varnish. and sludge on the engine surfaces which lower the operating efiiciency of the; engine. Also, due to oxidation effects, the viscosity of the oil is changed in. use so thatproper lubrication of the engine partsis not obtained; In; the; case ofi turbi-ne oils, the problem of oxidation is increased since; theoil normally becomes contaminated; with-water;

Lighter oil; fractions, such as: kerosene and gasoline, are

A: methodafor preparing; the al-kylthiohydroquinonesv u i i ed. herein. is.- set: forth. in. the copending application, Serial ,No. 271,300. AsdjSClOSCdr'lIlsaid application, the alkythiohydroq-uinones canbe. prepared ingood yield by" the reaction of an, aliphatic. mercaptanwith quinone: in. the. presence: of an, acidic catalyst, such asv p-toluene sulfonic. acid, at. relatively low. temperatures, viz.,=.frorn about 0 C. to. about 100 C.; the: best yields being;ob-=

tainedwhen anexcess. of mercaptan. is used in the read-- tion, i; e.,.'at least. 2 moles ofimercaptan per. mole of;

quinone. As further pointed: out in the. copending ap plication, thehigher. temperatures within: the aforesaid;

range favor the formation of mono-substituted alkyl,- thiohydroquinones, while the lower temperatures, i. e., from about. 0. C. to, about 10..15 C., favorthe formation of POlXflikXlthiDrSllbSIltlltCd hydroquinones.

The? amines, suitablefor: reaction with the; alkylthiohydroquinonesand.- formaldehyde to; form the products. herein: eontemplatedt'are; aliphatic, primary: amines; con taining from 1 to about 20 carbon atoms in the alkyl groups thereof. Thus, primary amines, such as ethyl amine, butyl amine, ethylhexyl amine, octyl amine, decyl ami'neydodecyl amine, tetradecyl amine, hexadecyl amine also subject to oxidative, deterioration in storage with;

the. formation of undesirable gum, color bodies, etc. therein. It is an object of this invention to provide a class of addition agents for petroleum oil fractions which are capable of substantially inhibiting the. oxidativeder terioration of such fractions. A. further. object. is. to. pro.-. vide petroleum compositions, such as lubricating oils and gasolines, which are highly stabilized against oxidation under the conditions of use, with respect to the lubricating oils, and in storage with respect to the gasolines.

In a copendingtap lication Serial No. 277300;. I have disclosed and claimed. oil compositionscontaining alkyl: thiohydroquinones as anti-oxidants- Also, I have described. and. claimed a. method. for preparing the alkylthioquinones and I have claimed certain tertiary alkylthiohydroquinones as new compositionsof matter. I have now found that alkylthiohydroquinones, such as disclosed in that application, can bereacted with formaldehyde and a primary or secondary aliphatic amine to form products which are outstanding anti-oxidants for petroleum oil fractions. As far as. is known, these alkylthiohydroquinone-formaldehyde-amine products have: not

ondary amine are thosehaving from I to. about; 20: carbon. atoms. in. the thioalkyl: substituent groups-,.. for example, monoalkylthio-substituted hydroquinones, such as. methylthiohydroquinone, t-butylthiohydroquinone, octylthiohydroquinone, t.-dodecylthiohydroquinone. and t-octa-- decylthiohydroquinone and dialkylthio-substituted' hydroquinones, such as di-t-butylthiohydroquinone, di-octylthiohydroquinone, didodecylthiohydroquinone and di- 9ctadecylthiohydroquinone.

and octadecyl amine, and secondary amines; such asdi n-butyl amine, di-Z-ethylhexyl amine, di-n-octyl amine, di-n-dodecyl amine, may, be-used. Also, mixed; diaglkyl amines in which the different alkyl radicals contain fromil to about 20 carbon atoms are suitable for the invention.

The reaction. of: the. alkylthiohydroquinone' with the formaldehyde and the primary: or secondary=amine takes place-readily at room temperature, ie.,, around 15-30" C. The reactants: arepreferably utilized in. the ratio of at least 2 moles of formaldehyde and. 2. moles of the amine per mole. of, the, alkylthiohydroquinone. The reaction is generally completed in from about /2 hour to about 3' hours. The reaction mechanism. is that of the Mannicha reaction (:Organic. Reactions, Adams et a1., vo1. I, chap. 10, John Wiley and-Sons, 1942,). Where the amine involved. is a secondary amine;v the reaction is clear cut, the product analyses: indicating; the formation of a mixture. of. 11); the. alkylthi'ohydroquinone, mono-substituted with the dialkylaminomethyl group (CH2N(R)2) and. (.2). the. alkylthioquinone-,v (ii-substituted with the dialleylaminomethyl. group; The reaction can be represented as follows:

S.R. atRt iNn+ 120.0

S-R 0H 0H, S-R

Where Rnand Rf, are: alkyl radicals,

'In the case; of; a primary amine, however, the: prod;- ucts: of. the: reaction; are not precisely; known, since. the. initial: condensation provides alkylthiohydroquinone, substituted: with methylalkylamine: groups; which still have. a: hydrogen .available for further condensation with: 1111-.- reacted alkylthiohydroquinone. The product is, therefore, a complex: mixture; which defies. exact analysis but whiclr is most: likely composed: of (1) alkylthiohydro- 'quinone, monoesubstituted withthe, mono-alkylaminomethyl; -.-CH2 -.N(H)R) radical, (2.) the: alkylthiohydroquinone, di-substituted with the mono-alkylaminomethyl radical,, and. additional productsaformed by further reaction of products 1 and 2 with unreacted alkylthiohydroquinone.

Patented Sept. 18., 1956 Table I summarizesthe results obtained by reacting alkylthiohydroquinones with formaldehyde and representative primary and secondary amines- All of these reactions were conducted under approximately the followof turbine oils. In this test. a 100-gram sample of test oil is 'used. An aluminum constant temperature block is used as a heating bath. The bath is maintained at a temperature of 203 F. The test tubes are 250 mm. x mm.

1 Calculated values for dlsubstituted product. 1 Calculated values for mono-substituted product.

Anti-oxidant action The ability of the products herein contemplated as oil anti-oxidants has been demonstrated by a number of tests conducted on various oil and gasoline blends thereof. The test procedures used and the results obtained were as follows:

Brown-Boveri turbine oil test This test determines the oxidation characteristics of turbine oils. In this test a ZOO-ml. sample of the test oil is placed in a 400-ml. tall form beaker provided with a glass cover having a center hole for the entrance of air. A polished copper plate (70 mm. x mm. x 1 mm.) is bent into a V shape and placed in the beaker so that the 70 mm. edge forms the base. The beaker is placed in a constant temperature oil bath maintained at 230 F. Air

is passed over the surface of the test oil at a rate of 2. H

liters per hour for 72 hours. The beaker is then removed from the bath and allowed to stand for 24 hours at room temperature. The Lovibond color and the N. N. (neutralization number) of the oil are then determined.

The A. S. T. M. oxidation test This test also determines the oxidation characteristics oils to corrode metal bearings.

d i g of ig 5 in size and are provided witha finger tube condenser and g a g i es 2 mo es i 3 an oxygen delivery tube. A catalyst coil prepared by iny e m 5 mm 9 a cen aqueous tel-winding 20 inches of No. 18 copper wire with 20 inches used' The alkylthlohydmqumone was first med wlth of N0 18 iron Wire is laced in each tube Four tubes theamine and the formaldehyde solution was added with ea h t 25 r t d f h t t stirring over a period of about hour with the tempera- 10 0 g i o f use eac cs 01 ture of the reaction mixture being maintained at about we o f e Water 15 introduced mm each tube C. The reaction mixture was then stirred for and 0.3- '0.05 liter of oxygen per hour are passedthrough several hours at room temperature, the water-separated h b r the duratlon f the tes Water is added out, and then topped to a pot temperature of -475 C. when necessary to p? UQQP 5 I111- p The under 2 mm. pressure to obtain the final product. It will 15 tubes are removed one tube at a tlme at desired intervals be seen from the data in Table I that the product from and the Lovibond color and N. N. (neutralization num- Example 2 is mainly the di-dialkylaminomethyl-substiher) f then determined p g q ig f of Examples The reference oil used in both the Brown-Boveri and an are .mlxmre.s o t a y roqumone (a v A. S. T. M, oxidation test was a solvent-refined, Mid-Conmono-substituted with the dialkylammomethyl group and 20 distillate havin a S ecific ravit of 0 86 a h (b) (ii-substituted with the dialkylaminomethyl group, o g p g y o and the product from Example 5 is mainly the mono-di- P 1 0f 405 a lf of at 100 R a1kylaminomethyl-substituted alkylthiohydroquinone. The results obtained are shown in Table II.

TABLE I Reaction of amines with alkylthiohydroquinones Yi 1d i 't e ercen i 1 3 6 1? R gcmnt Product Wt. (6.)

0 g. (0. 05 mol) t-butylthiohydroquinone t 1 {27 g. (0; 15 mol) 25% aqueous dimethylamine 1 s 2369???? sses es-see Y F. .-b lth' -bisd'- t 6.56 6.25 2 (0- 225 101) di'n'butylamme g i n gggghyfi iydgqum or rg u y 37 1 5 33 t 5 7 19. 5 g. (0. 225 mol) 36% aqueous formaldehyde" i t of ten; butylthiodmethyb {$25 0- igfl mg q a s .r: p

13g. (0.1511201) 36% aqueous formaldehyde ggggggg g g f 2 Y 5111mm? y 13.98 1 4.54.

. tt.- lh'-di- -bt;la has; ilS.,li s f 9. l as as 50%: ioIemol 36% aqu ous roriiih 'd. gggggggg ggf n blty ammmet yl) 1 5.23 5.03 32 t'dodecylthmhydmqumone- Mainly tert. dodecylthio di n butylamino t 3. 04 7. 34 5 a9 0.3 ld'- -b 1 50 25 E. 20.3 31 81 36 7: ati e h pr laldehyden methylhydmqumme' I 26 g. 0.08 mol) t dodecylthiohydroquinon 6 {15 g. 50. 2 mol) n-butylamine 29 2. 26 10. 65

17 g. 0. 2 Incl) 36% aqueous formaldehyde TABLE II Brown-Boveri and A. S. T. M. oxidation tests v B 'BJ Oxidation Test A. S. T. M. Oxidatiou Test Product added Wt. Lovi- Wt. Lovipercent bond N. N. percent Hrs. bond N. N. Ooncn. Color Conen. Color 0 0. 1 0. 01 None 55 0. 24 24 3 0.05

72 172 5. 1 Example No. F2 I. fi-- 0.2 10 0.01 .16-.. ""6".

.xamp e o. 0

l Brown-Boveri.

The bubble test This test determines the relative tendency of lubricating In this test, a connecting rod bearing having a cadmium-silver alloy surface is carefully weighed (about 6 grams) and is placed in a 20 mm. x 25 mm. test tube together with 30 grams of the test oil. A 5 mm. glass inlet tube, drawn to about 1 mm. I. D. for about 30 mm. at one end is placed in the tube. The test tube is placed in a constant temperature bath maintained 75 at 175 C. and air is blown through the test oil at a rate of 2 liters per hour for22 hours. The test piece is' then The German tar test This test determines the antioxidant properties of an oil. In this test, a ISO-gram oil sample is placed in a 250 ml. extraction flask in an oil bath maintained at 120 C. The flask is equipped with a cork having. a 6 mm. I. D. inlet tube extending therethrough to the bottom of the flask and a vent tube. Oxygen gas is bubbled through the oil at the rate of 2 bubbles per second for 70 hours. The N. N. (neutralization number) of the oil is then measured. The reference oil used for this test was a highly acid-refined coastal distillate suitable for use in transformers. It had a specific gravity of 0.871, a flash point of 310 F., and a Saybolt Universal viscosity of 69- :seconds at 100 F. The results of these tests are summarized in Table IV.

TABLE IV German tartest The Lauson oxidation stability ,test

This test determines oil deterioration as measured 'by corrosion of copper-lead bearings. In this test, one gallon of oil is used in a Lauson. single-cylinder, 4-cycle, liquid-cooled gasoline engine with splash lubrication, the engine having a weighed copper-lead hearing. The engine is operated under the following conditions for 100 hours.

Oil temperatr1re--270 F Jacket temperature2 12 F. Speed-1825 R. P. M. One-half throttle 13-1 air-fuel ratio Oil added every 20 hours The fuel used was a controlled Mobilgas Special blend (40% thermal, 30% catalytically cracked and 30% straight run plus 2.5 cc. tetraet-hyl lead per gal.). The

engine bearing is weighed at the end of the test to determine the weight loss thereof. The results are shown in Table V. The reference oil used was the same as that used in the Bubble Test.

6 TABLE V Lauson 0S-2 oxidation test Bearing Wt. i Wt. Loss (G) Product Added Percent Av. of Top Conan. and Bottom None 0, 510 Example No. 4 0. 5 0. 080

Gasoline. storage: test This testde'term-ines' the gram stability'of gasoline under simulated field storage conditions. In this test, 2 or more 1500-ml. samples of the gasoline are stored in halfgallon brown bottles with 200 m1. of distilled water and 2 in. by 9 in. polished iron strips-in. each bottle. The bottles are filled with a slotted cork to permit breathing of the samples and at the same time prevent contamination by foreign matter. The samples are stored in a room at a temperature of to F. The samples are tested'in turn at specified time intervals and then discarded.- The glass dish gum formed during the period of storage up to the time of the test is taken as a measure of the gum stability of the gasoline. The reference gasoline used in these tests was a KOH-treated thermal gasoline. The results are shown in Table VI.

TABLE VI Gasoline storage test Glass Dish Gum,

Mg. Gum/'Ml. Gasoline Tested- 20-Days 50 Days KOH-treated thermal gasoline 97. 3 279 KOH-treated thermal gasoline containing 10 lb./1,000 bbls. of Example No. 2 4. 9 6. 6

cent, by weight, to about 10 per cent, by weight, may be used, although usually from about 0.1. per cent to about 2 per cent provide satisfactory oxidation inhibition. The additives of this invention may, of course, be added to petroleum fractions along with other additive agents designed to improve various other characteristics of such fractions, e. g., pour depressants, extreme pressure agents, detergents and the like. A

Although the invention has been illustrated herein by the use of specific examples of my additive products and in particular petroleum media, it is not intended that the scope of my invention be in any way limited thereby, but only as shown in the accompanying claims.

What is claimed is:

1. A petroleum lubricatingv oil containing a minor amount, sufficient to stabilize said oil against oxidation, of a compound of the formula R-s [outwit )2].

where R and R are alkyl radicals having from 1 to about 20 carbon atoms, and m and n are integers from 1 to 2.

e 2. A petroleum' lubricating oil containing a minor '7 amount, sufiicient to stabilize said oil against oxidation, of a compound of the formula where R and R are alkyl radicals having from 1 to about 20 carbon atoms, and n is an integer from 1 to 2.

3. A gasoline containing a minor amount, suificient to stabilize said gasoline against oxidation, of a compound of the formula 7 ms), icmm 'nn where R and R are alkyl radicals having from 1 to about 20 carbon atoms, and m and n are integers from 1 to 2.

4. A gasoline containing a minor amount, sufiicient to stabilize said gasoline against oxidation, of a compound of the formula where R and R are alkyl radicals having from 1 to about 20 carbon atoms, and n is an integer from 1 to 2.

5. A petroleum lubricating oil containing a minor amount, suflicient to stabilize said oil against oxidation, of a compound of the formula 7 6. A petroleum lubricating oil containing a minor amount, suflicient to stabilizesaid oil against oxidation, of a compound of the formula where n is an integer from 1 to 2.

7. A petroleum lubricating oil containing a minor amount, suflicient to stabilize said oil against oxidation, of a compound of the formula where n is an integer from 1 to 2.

8. A petroleum lubricating oil containing a minor amount, sufficient to stabilize said oil against oxidation, of a compound of the formula 9. A gasoline containing a minor amount, sufficient to stabilize said gasoline against oxidation, of a compound of the formula (t-blltyl) S [C'HzN( C 4H0) 211 where R and R are alkyl radicals having from 1 to about 20 carbon atoms, and m and n are integers from 1 to 2 11. As a new composition of matter, a compound of the formula 13. As a new composition of matter, a compound of the formula 015! where n is an integer from 1 to 2.

14. As a new composition of matter, a compound of the formula (t-octyl) S [CHr-N (C4Ho) all where n is an integer from 1 to 2.

15. As a new composition of matter, a compound of the formula 16. A petroleum fraction containing a minor amount, sufiicient to stabilize said fraction against oxidation, of a sulfurand nitrogen-containing reaction product formed by reacting (1) an alkylthio-substituted hydroquinone having no substituents other than unsubstituted alkylthio groups, said alkylthio groups containing from 1 to about 20 carbon atoms and being attached through the sulfur atom thereof to the hydroquinone nucleus, with (2) formaldehyde and (3) a primary aliphatic amine having from 1 to about 20 carbon atoms per alkyl group thereof, at a temperature of from about 15 C to about 30 C., and for a time period of from about /2 hour to several hours.

17. As a new composition of matter, a sulfurand nitrogen-containing reaction product formed by reacting (1) an alkylthio-substituted hydroquinone having no subs-tituents other than unsubstituted alkylthio groups, said alkylthio groups containing from 1 to about 20 carbon atoms and being attached through the sulfur atom 5 thereof to the hydroquinone nucleus, with (2) formaldehyde and (3) a primary aliphatic amine having from 1 to about 20 carbon atoms per alkyl group thereof, at a temperature of from about 15 C. to about 30 C.,

and for a time period of from about /2 hour to several 10 hours.

References Cited in the file of this patent UNITED STATES PATENTS 2,553,441 Chenicek May 15, 1951 

1. A PETROLEUM LUBRICATING OIL CONTAINING A MINOR AMOUNT, SUFFICIENT TO STABILIZE SAID OIL AGAINST OXIDATION, OF A COMPOUND OF THE FORMULA
 10. AS A NEW COMPOSITION OF MATTER, A COMPOUND OF THE FORMULA 